Flare stack gas burner

ABSTRACT

A flare stack gas burner for waste combustible gases at both low and high pressure and under all flow conditions including low pressure gas without any high pressure gas stream from oil refineries and the like is disclosed with separate delivery systems for the combustion gases which includes a stack with a central low pressure gas delivery tube which has at its top outwardly extending vanes with gas delivery slots, the vanes being disposed for imparting a swirling action to the burning gas. The delivery pipe is closed at the top by a closure plate with flame retention openings. Air at variable low pressure is delivered into the stack at the bottom and flows upwardly between the vanes for smokeless burning. A pipe is provided for high pressure gas mounted exteriorly of the stack for delivery to a manifold ring and thence to delivery pipes with angularly disposed tips for enhancement of the burning of the gases. An optional fluidic seal can be provided in the low pressure gas supply. Ignitors and pilots are provided exteriorly of said stack.

1 nite States Straitz, 1H

[11] 3,822,985 July 9,1974

1 1 FLARE STACK GAS BURNER [75] Inventor: John F. Straitz, I111,Jenkinton, Pa.

[73] Assignee: Combustion Unlimited, Incorporated, Elkins Park, Pa.

[22] Filed: Aug. 13, 1973 [21] App]. N0.: 387,710

52] us. Cl. 431/284, 431/202 51 Int. Cl rzs 9/00 [58] Field of Search431/202, 278, 284, 285

[56] References Cited UNITED STATES PATENTS 2,222,822 11/1940 Nordensson431/285 3,358,736 12/1967 Reed et al..... 431/285 10/1972 Reed 10/1972Turpin 431/202 Primary Examiner-Carroll B. Dority, Jr. Attorney, Agent,or Firm-Zachary T. Wobensmith, 2nd; Zachary T. Wobensmith, 111

[ ABSTRACT A flare stack gas burner for waste combustible gases at bothlow and high pressure and under all flow conditions including lowpressure gas without any high pressure gas stream from oil refineriesand the like is disclosed with separate delivery systems for thecombustion gases which includes a stack with a centrallow pressure gasdelivery tube which has at its top outwardly extending vanes with gasdelivery slots, the

vanes being disposed for imparting a swirling action to the burning gas.The delivery pipe is closed at the top by a closure plate with flameretention openings. Air

at variable low pressure is delivered into the stack at the bottom andflows upwardly between the vanes for smokeless burning. A pipe isprovided for high pressure gas mounted exteriorly of the stack fordelivery -to a manifold ring and thence to delivery pipes with angularlydisposed tips for enhancement of the burning of the gases. An optionalfluidic seal can be pro- "vided in the low pressure gas supply. lgnitorsand pilots are provided exteriorly of said stack.

7 Claims, 4 Drawing Figures I FLARE STACK GAS BURNER BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates to flarestack gas burners for both low and high pressure waste gas fromrefineries and the like for smokeless burning without steam.

2. Description of the Prior Art In industrial operations andparticularly in the operation of oil refineries it becomes necessaryfrom time to time to burn various quantities of combustible gaseousmaterials. The characteristics of these materials both as to compositionand pressure varies considerably. Ecological considerations require thatthe gases be burned and that the combustion be carried out withoutdischarge of unburned carbon particles in the form of smoke into theatmosphere both for the lowest pressure and the highest pressure of thewaste gases and over the whole range.

Various flare stack gas burners have heretofore been proposed for highand low pressure gas but these have had serious limitations,particularly because of the difficulty of designing a structure thatwill operate smokelessly with both low and high pressure combustiblegases and over a wide range of flows.

In addition, at some locations, an inadequate supply of steam would beavailable for smoke suppression as used in many flare stack burners, andother considerations such as climate might also preclude the use ofsteam for smoke suppression.

Among the burners heretofore proposed are those shown in the US. Patentsto Vemer et al., No. 2,761,496; Webster, et al. No. 2,891,607;Shellentrager, No. 2,506,972; Rodman, No. 2,537,091 Zink et al., No.2,779,399; Campbell et al., No. 2,802,521; Zink et al., No. 3,143,424;and in Canadian Patent to Williams, No. 69l,894, and in British Patentto British Petroleum Co., et al. No. 795,664. I

None of these burners or others previously available provide forsmokeless burning of low and high pressure waste gases by use ofseparate gas delivery systems.

SUMMARY OF THE INVENTION In accordance with the invention a flare stackgas burner is provided for burning of gases from two low and highpressure separate gas delivery systems and over a wide range of flow bystructure which includes a low pressure delivery pipe within the stackclosed at the top by a closure plate, with flame retention openings, andcommunicating with attached vanes angularly disposed in a horizontalplane from radial lines through the center of the stack, the vaneshaving slots at their top margins for low pressure flare gas delivery, alow pressure air blower is provided at the bottom of the stack forintroduction of air as a combustion supporting media and which air flowspast the vanes.

A high pressure gas line delivers waste combustible gas at high pressureto a ring outside the stack and thence through inclined pipes toupwardly and angularly inclined burner nozzles for smokeless combustion.

' Ignitors and pilots are also shown.

It is a further object of the invention to provide a flare stack gasburner of the character aforesaid in which the combustible low pressurewaste gas and air at the vanes burns smokelessly.

It is a further object of the invention to provide a flare stack gasburner in which the combustible waste gas at high pressure is deliveredat the top of the stack for smokeless combustion.

It is a further object of the invention to provide a flare stack gasburner of the character aforesaid in which the component parts aresimple, sturdy, trouble free, require a minimum of maintenance, andwhich is more effective in its burning of the waste gas than the flareburners heretofore available.

Other objects and advantageous features of the in vention will beapparent from the description and claims.

BRIEF DESCRIPTION'OF THE DRAWINGS The nature and characteristic featuresof the invention will be readily understood from the followingdescription taken in connection with the accompanying drawing formingpart hereof, in which:

FIG. 1 is a view partly in elevation and partly in vertical section of.a flare stack in accordance with the invention;

FIG. 2 is a top plan view of the flare stack of FIG. 1;

FIG. 3 is a horizontal sectional view taken approximately on the line3--3 of FIG. 2, and

FIG. 4 is an enlarged vertical sectional view taken on the line 4-4 ofFIG. 2.

It should, of course, be understood that the description and drawingsherein are illustrative merely and that various modifications andchanges can be made in the structure disclosed without departing fromthe spirit of the invention.

Like numerals refer to like parts throughout the several views.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularlyto the drawings, a vertical stack pipe 10 is shown, circular inhorizontal cross section and at the bottom of which is mounted an airinlet pipe 11 with an axial fan (not shown) and a damper (not shown) toprovide variable low pressure air into the interior of the stack pipe 10for combustion of the waste gas. The stack pipe 10 has a burner tipportion 10a which may be detachably connected for replacement and of aheight of the order of eight feet. The pipe 10 is preferably fabricatedof steel and coated to reduce rust and may be of the order of fifty feetin height, and of a diameter of the order of two feet.

The stack pipe 10 has, in spaced relation thereto, a centrally disposedinterior low pressure delivery pipe 12 with its lower terminuscommunicating with the supply of low pressure waste gas'to be burned.The pipe 12 is closed at the top by an annular closure plate 15 whichcan be provided with a plurality of openings 16 therethrough forimproved flame retention as hereinafter pointed out and in a specificembodiment may have a diameter of the order of ten inches.

The pipe 12 has extending outwardly therefrom a plurality of fixedtilted vanes 18. The vanes 18 (see FIG. 4) are shown as made withconverging side wall plates 19 and 20, closed at the bottom by a bottomwall 21 and at the outer end by an end wall 22 and with intennediatestiffeners 23 parallel to the end wall 22. The plates 19 and 20 areseparated at the top to provide a gas delivery slot 24 inclined withrespect to the horizontal, and at their inner ends the vanes 18 havetheir interiors in communication with the pipe 12.

The vanes 18 and their gas delivery slots 24 are each at an angle, in ahorizontal plane, to a radial line through the center of the pipe 12,which with the tilting imparts a swirling motion to the gas deliveredthrough the slots 24 and with respect to the openings 16 in the closureplate 15.

In larger flare stacks, in order to prevent downflow in the interior ofthe stack pipe 10, whether by external wind conditions or contraction bycooling of hot gas in the system, and also to reduce fluid oscillations,a fluidic diode (not shown) such as that shown in my US. Pat. No.3,730,673, dated May 1, 1973 for Vent Seal, can be employed in theburner tip portion a or lower in the stack 10.

A high pressure gas supply pipe 30 is provided exteriorly mounted on thestack pipe 10 and extendng upwardly to a horizontal ring manifold 31.The ring 31 has gas delivery pipes 32 connected thereto.

Each of the pipes 32 has a vertically upwardly extending portion 33 andan angularly disposed terminal end 35 with a tip 36.

The tip 36, if desired can be similar to that shown in the BitterlichUS. Pat. No. 3,463,602, dated Aug. 26, 1969.

The tip 36 and terminal end 35 are inclined and turned or angularlydisposed to direct the high pressure gas so as to enhance the swirlingaction of the burning gases from the high pressure supply.

A plurality of gas pilots 40 are provided with their .heads 41 or upperterminii between the pipes 32. The

pilots 40 can be of the venturi air inspirating type and connected to agas manifold ring (not shown) to which combustible gas is suppliedthrough a pipe 43. The gas pilots 40 can be supported by brackets 44secured to the pipe 10.

In order to ignite the gas pilots 40, an igniter pipe 45 is providedthrough which a gas flame is directed when desired. The igniter pipe 45can be supported by a bracket (not shown) secured to the pipe 10.

In use, the pilots 40 are continuously burning, ignition being effectedby flame delivered through the igniter pipe 45.

Waste gas at low pressure to be burned is delivered through pipe 12where it passes upwardly and then outwardly into the vanes 18 fordelivery through the slots 24 in a plurality of sheet flame patternsoffset from horizontal radii through the vertical axis and inclined bythe tilting of vanes 18, as determined by the positioning of the slots24. Air is delivered between the vanes 18 and along the margins of theflames from the slots 24 through the pipe 10, aided as desired by theblower which provides the quantity of air needed for smokelessoperation, as called for by a flow sensor (not shown) which is connectedinto the low pressure gas supply pipe 12.

The flame retention openings 16 permit small streams of gas to bedischarged to burn above the closure plate 15 and prevent adverse effectof wind on the flame sheets from the slots 24.

If waste gas at high pressure is also or alternatively to be burned itis supplied through pipe 30 to the ring manifold 31 thence through pipes32 to tips 36. The inclination of pipes 32 and the inclination of thetips 36 together with the disposition of the spaces between the vanes 18combine to produce a swirling action which permits complete smokelesscombustion of the waste gas.

At high flow rates of only high pressure gas, the swirling actionproduced by the tips 36 is suflicient to produce smokeless operationwithout using the air blower.

With high flows of low pressure gas at the same time as high flows ofthe high pressure gas, air supply from the blower is desirable.

With low flow of low pressure gas and a large flow of high pressure gas,the swirling action brought about by the tips 36 produces smokelessaction of both streams.

Both low pressure waste gas and high pressure waste gas can be burnedsimultaneously, and over a very wide range of flow conditions.

I claim:

1. A flare stack gas burner for waste gas having an outer stack pipewith a burner tip portion at its upper end comprising a combustible lowpressure waste gas delivery pipe extending upwardly within said stackpipe,

a plurality of outwardly extending hollow vanes at the upper end of theburner tip portion of said delivery pipe with spaces therebetween andhaving upwardly facing gas delivery openings connected to said gasdelivery pipe for discharge of said low pressure waste gas for burning,

means associated with said stack pipe for supplying air therethrough fordelivery of air through the spaces between said vanes for combustion ofwaste gas delivered through said pipe,

said vanes being disposed to impart a swirling action to the gasdelivered therefrom and to the air delivered therebetween,

a combustible high pressure waste gas supply pipe exterorly mounted withrespect to said stack pipe, an

a plurality of burner tips connected to said supply pipe and disposedbeyond said burner tip portion of said stack pipe and directing saidhigh pressure gas into the path of air from between said vanes, saidburner tips being angularly inclined to swirl the gases passingthere-through.

2. A flare stack gas burner as defined in claim 1 in which said highpressure waste gas supply pipe has a plurality of gas delivery pipesconnected thereto on which said burner tips are carried.

3. A flare stack gas burner as defined in claim 2 in which said highpressure gas delivery pipes are inclined upwardly and angularly.

4. A flare stack gas burner as defined in claim 2 in which said gasdeivery pipes are connected to a ring manifold to which said supply pipeis connected.

5. A flare stack burner as defined in claim 1 in which said low pressurewaste gas delivery pipe has an end closure provided with flame retentionports. 6. A flare stack gas burner as defined in claim 1 in which saidvanes are tilted. 7. A flare stack gas burner as defined in claim 1 inwhich said vanes have their slots disposed at an angle to a radiusthrough the vertical longitudinal axis of said pipe.

1. A flare stack gas burner for waste gas having an outer stack pipewith a burner tip portion at its upper end comprising a combustible lowpressure waste gas delivery pipe extending upwardly within said stackpipe, a plurality of outwardly extending hollow vanes at the upper endof the burner tip portion of said delivery pipe with spaces therebetweenand having upwardly facing gas delivery openings connected to said gasdelivery pipe for discharge of said low pressure waste gas for burning,means associated with said stack pipe for supplying air therethrough fordelivery of air through the spaces between said vanes for combustion ofwaste gas delivered through said pipe, said vanes being disposed toimpart a swirling action to the gas delivered therefrom and to the airdelivered therebetween, a combustible high pressure waste gas supplypipe exteriorly mounted with respect to said stack pipe, and a pluralityof burner tips connected to said supply pipe and disposed beyond saidburner tip portion of said stack pipe and directing said high pressuregas into the path of air from between said vanes, said burner tips beingangularly inclined to swirl the gases passing there-through.
 2. A flarestack gas burner as defined in claim 1 in which said high pressure wastegas supply pipe has a plurality of gas delivery pipes connected theretoon which said burner tips are carried.
 3. A flare stack gas burner asdefined in claim 2 in which said high pressure gas delivery pipes areinclined upwardly and angularly.
 4. A flare stack gas burner as definedin claim 2 in which said gas deivery pipes are connected to a ringmanifold to which said supply pipe is connected.
 5. A flare stack burneras defined in claim 1 in which said low pressure waste gas delivery pipehas an end closure provided with flame retention ports.
 6. A flare stackgas burner as defined in claim 1 in which said vanes are tilted.
 7. Aflare stack gas burner as defined in claim 1 in which said vanes havetheir slots disposed at an angle to a radius through the verticallongitudinal axis of said pipe.